1. Introducing…
Mr. MOLE
Hellooo Students!!!

2. Chemistry Joke
Q: What did the proton say to the electron to make him happy?
A: Something positive!

3. What is a MOLE? Abbreviated “mol”
The amount of a substance that contains
6.02 x 1023 representative particles.
6.02 x 1023 is called AVOGADRO’S NUMBER.
It is an equivalency—a conversion factor
Just like…1 dozen = 12 pieces,
1 mole = 6.02 x 1023 pieces

4. Why 6.02 x 1023???
Because atoms are so small, Avogadro’s number has to be pretty big. How big?
Scientists use this number because…
It is the number of particles in 12 grams of carbon-12
602,000,000,000,000,000,000,000

5. If you had a mole of water molecules, how much water do you think this would be?
1 mole of water molecules (6.02 x 1023 molecules of water) is only about 18 mL of water !!

6. 1 MOLE of Atoms

7. Using Moles in Chemistry
Definition – the amount of a substance that contains 6.02 x 1023 representative particles.
What is a representative particle?
It is whatever you are counting:
Molecules
Formula units
Atoms
Ions

8. A Typical Question: How many molecules of CO2 are there in 4
A Typical Question: How many molecules of CO2 are there in 4.56 moles of CO2 ?
Our representative particle in this question is a molecule—it is what we are counting.
We can use dimensional analysis:
1 mol CO2 = 6.02 x 1023 molecules CO2
6.02 x 1023 molecules CO2
4.56 mol CO2
1 mol CO2
(4.56) 6.02 x 1023 molecules CO2= x 1024 molecules CO2

9. Moving On… The MOLAR MASS!!
Now that we can find how many representative particles are in a given number of moles, and…
How many moles are represented by a given number of representative particles,
We need to learn about the mass of a mole.
The MOLAR MASS!!

10. Measuring the Mass of Moles
Remember atomic mass?
The amu (atomic mass unit) is one twelfth the mass of a carbon-12 atom.
Since the mole is the number of atoms in 12 grams of carbon-12…
The decimal number on the periodic table (average atomic mass) is ALSO the mass of 1 mole of those atoms in grams.

11. Finding the Molar Mass of Elements
amu
grams / mole
Using the periodic table, what is the molar mass of…
Aluminum
Lead
Notice, we’re still talking about 1 mole. Each mole has the same number of particles (6.02 x 1023), just different masses!
26.98 g/mol
26.98 g Al = 1 mol Al
g/mol
g Pb = 1 mol Pb

12. Finding the Molar Mass of a Compound
It’s simple: Just add up its atomic masses.
Example: What is the molar mass of water?
H2O
2 H = 2 x = g/mol
1 oxygen = 1 x = g/mol
2.02 g g = g/mol
molar mass of water = g/mol

13. Calculate These Molar Masses:
Mg3(PO4)2
g/mol
C12H22O11
g/mol

14. Molar mass is the generic term for the mass of one mole of any substance
Also called:
Gram Molecular Mass (molecules)
Gram Formula Mass (ionic cmpds)
Gram Atomic Mass (elements)

15. Practice Problem Using Molar Mass
How many grams are in 0.25 mol of NaCl?
Find the molar mass. (This will be the conversion factor.)
Na: g/mol; Cl: g/mol;
NaCl: = g/mol
Use dimensional analysis to solve.
58.45 g NaCl = 1 mol NaCl
0.25 mol NaCl
58.45 g NaCl
=15 g NaCl
1 mol NaCl

16. Another Practice Problem
How many moles are in 25 g of NaCl?
Find the molar mass (This will be the conversion factor.)
Na: g/mol; Cl: g/mol
NaCl: = g/mol
Use dimensional analysis to solve.
1 mol NaCl = g NaCl
25 g NaCl
1 mol NaCl
=0.43 mol NaCl
58.45 g NaCl

17. ChemistryJoke
Q: What kind of music does a chemist listen to?
A: Heavy Metal!